Automated flight throttle control

ABSTRACT

Automated throttle control is described herein. One disclosed example method includes calculating, using a processor, a thrust resolver angle based on a flight condition of an aircraft, and controlling a throttle from moving past at least one of the thrust resolver angle or a range defined by the thrust resolver angle to maintain the aircraft in a preferred flight mode.

FIELD OF THE DISCLOSURE

This patent relates generally to aircraft and, more particularly, toautomated flight throttle control.

BACKGROUND

Some known autothrottle systems are used to control/maintain an amountof thrust provided by an aircraft during maneuvers and/or cruise.Typically, an autothrottle system can be placed into a hold mode, inwhich the autothrottle is no longer controlling the amount of thrustprovided by the aircraft. Known autothrottle systems do notautomatically change to a different mode after the autothrottle systemhas been placed into the hold mode unless commanded by the pilot.

SUMMARY

An example method includes calculating, using a processor, a thrustresolver angle based on a flight condition of an aircraft, andcontrolling a throttle from moving past at least one of the thrustresolver angle or a range defined by the thrust resolver angle tomaintain the aircraft in a preferred flight mode.

Another example method includes analyzing, using a processor, a receivedflight input and at least one flight condition to determine whether theflight input will place the aircraft in a state different from apreferred flight state. The example method also includes, upondetermining that the flight input will not place the aircraft in thestate different from the preferred flight state, enabling anautothrottle control to be placed into a hold mode.

An example tangible machine readable medium has instructions storedthereon, which when executed, cause a processor to determine that aflight input of an aircraft will cause the aircraft to be in anon-preferred flight condition, and based on the determination, changean autothrottle mode of the aircraft to maintain the aircraft in apreferred flight condition.

An example apparatus includes a sensor of an aircraft to determine aflight condition of the aircraft, a processor to calculate at least oneof a throttle limit or a throttle range to maintain the aircraft in apreferred flight condition, and an electromechanical mechanism tocontrol a throttle lever from moving beyond the at least one of thethrottle limit or the throttle range to maintain the aircraft in thepreferred flight condition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an example aircraft in which the examples disclosed herein maybe implemented.

FIG. 2A is an internal view of an example cockpit of FIG. 1.

FIG. 2B is a detailed view of an example throttle control of the examplecockpit of FIGS. 1 and 2.

FIG. 3 illustrates an example throttle control plot in accordance withthe teachings of this disclosure.

FIG. 4 is a schematic overview of an example algorithm to implement theexamples disclosed herein.

FIG. 5 is an example throttle control system that may be used toimplement the examples disclosed herein.

FIG. 6 is a flowchart representative of an example method that may beused to implement the example throttle control system of FIG. 5.

FIG. 7 is a flowchart representative of another example method that maybe used to implement the example throttle control system of FIG. 5.

FIG. 8 is a flowchart representative of another example method that maybe used to implement the example throttle control system of FIG. 5.

FIG. 9 is a block diagram of an example processor platform capable ofexecuting machine readable instructions to implement the example methodsof FIGS. 6-8.

The figures are not to scale. Instead, to clarify multiple layers andregions, the thickness of the layers may be enlarged in the drawings.Wherever possible, the same reference numbers will be used throughoutthe drawing(s) and accompanying written description to refer to the sameor like parts. As used in this patent, stating that any part is in anyway positioned on (e.g., positioned on, located on, disposed on, orformed on, etc.) another part, means that the referenced part is eitherin contact with the other part, or that the referenced part is above theother part with one or more intermediate part(s) located therebetween.Stating that any part is in contact with another part means that thereis no intermediate part between the two parts.

DETAILED DESCRIPTION

Automated flight throttle control is disclosed herein. Some knownautothrottle systems of aircraft are used to control/maintain an amountof thrust provided by the aircraft during maneuvers and/or cruise, forexample. These known autothrottle systems allow an aircraft to be placedinto a hold mode in which the autothrottle system is overridden and/orsuspended based on a flight input from a pilot. As a result, the pilotmay be able to place a throttle setting of the aircraft into anon-preferred condition and/or place the aircraft in a lower performancemode. In known typical systems, once placed into the hold mode, theautothrottle system does not automatically change modes without beingcommanded to do so by the pilot.

The examples disclosed herein prevent aircraft from entering thenon-preferred flight condition regardless of whether an autothrottlehold mode has been initiated/enabled. The examples disclosed hereincontrol and/or set the throttle range and/or throttle setting(s) of anaircraft based on flight conditions of the aircraft and/or a flightinput received (e.g., a flight input command, a cockpit command, etc.).In some examples, the flight conditions are used to calculate a thrustresolver angle (e.g., a thrust resolver limit) that restricts (e.g.,inhibits motion) and/or limits a throttle (e.g., a throttle control).For example, a throttle control (e.g., an automated throttle control)may be restricted from moving past the defined thrust resolver angle(TRA) and/or a range defined by the thrust resolver angle. In someexamples, an electromechanical control system may prevent physicalmovement of the throttle and/or a throttle lever (e.g., a throttlestick) beyond the calculated thrust resolver angle, for example. Forexample, an actuator and/or solenoid may be used to control (e.g.,prevent from moving past) a pivot of the throttle and/or the throttlelever from moving beyond an angle and/or an angular range defined by thecalculated thrust resolver angle.

In other examples, a flight input for the aircraft is compared/analyzedrelative to a calculated thrust resolver angle, which is determinedbased on flight condition(s), and the flight input may not be initiatedbased on the calculated thrust resolver angle. In particular, the flightinput may be compared to a preferred thrust/velocity setting that iscalculated based on the flight condition(s) to determine whether toexecute the flight input and/or enable a throttle override/hold mode.

In other examples, the aircraft is returned to another autothrottle modefrom a hold mode when a flight condition of the aircraft corresponds toa non-preferred flight condition of the aircraft. For example, anautothrottle mode may be automatically changed when a velocity of theaircraft moving below a defined range and/or a thrust setting is setbelow a calculated allowable and/or preferred thrust resolver angle.

As used herein, the terms “flight input command” or “flight input” mayrefer to a manual command issued at a cockpit or a command to enter anautomated flight mode (e.g., a selected automated mode, an autopilot, aflight level change (“FLCH”) mode, a take-off and go around (“TOGA”)command, a vertical navigation (“VNAV,” “VNAV IDLE,” “VNAV HOLD”)command, etc.). In other words, the terms “flight input” or “flightinput command” may refer to manual control or an initiation of anautomated flight mode, for example. As used herein, the term “flightcondition” may encompass, but is not limited to, air speed, altitude,terrain topography, wind speed, air conditions (e.g., turbulence),attitude, yaw, pitch, roll and/or weather, etc.

FIG. 1 illustrates an example aircraft 100 in which the examplesdisclosed herein may be implemented. The aircraft 100 of the illustratedexample includes a fuselage 102 with a cockpit 104, wings 105 withengines 106 and control surfaces (e.g., flaps, ailerons, tabs, etc.)108, which are located at a trailing edge of the wings 105 and may bedisplaced or adjusted (e.g., angled, etc.) to provide lift duringtakeoff, for example. The example aircraft 100 also includes stabilizers112 with rudders 114 and elevators 116. In some examples, throttles ofthe respective engines 106 are controlled to vary and/or control avelocity of the aircraft 100. In this example, the resultant thrust ofthe engines 106 along with movement of the control surfaces 108, therudder 114 and/or the elevators 116 are used to control/direct theaircraft 100 during a maneuver such as a controlled descent (e.g., acontrolled and/or rate controlled increase/decrease in altitude) and/orexecution of an automated flight program such as a TOGA program, or aVNAV program, etc.

FIG. 2A is an internal view of the example cockpit 104 of FIG. 1. As canbe seen in the illustrated example of FIG. 2A, the cockpit 104 includesa flight stick 202, an instrumentation panel 204 and a throttle control206, which includes a throttle lever (e.g., a throttle stick) 208. Inoperation, a pilot in the cockpit 104 may read and/or obtain flight dataand/or flight condition data of the aircraft 100 from theinstrumentation panel 204. Based on this data, one or more controls ofthe aircraft 100 may be utilized by the pilot to direct the aircraft 100during flight. In this example, thrust of the aircraft 100 is controlledby the throttle lever 208, the throttle control 206, in general, and/orcontrols within the cockpit 104 related to autothrottle settings (e.g.,controls in the instrumentation panel 204, etc.).

FIG. 2B is a detailed view of an example throttle control 206 of theexample cockpit 104 of FIGS. 1 and 2A. In the illustrated example ofFIG. 2B, the throttle lever 208 may be pushed and/or pivoted toward oraway from the front of the aircraft 100 to vary an amount of thrustoutput from the engines 106. For example, a pilot may push the throttlelever 208 forward toward the front/fore of the aircraft 100 to increasea thrust of the engines 106. Similarly, the pilot may pull back and/orpivot the throttle lever 208 back toward the rear/aft of the aircraft100 to reduce thrust output and/or throttle of the engines 106.

As a result of being able to move the throttle lever 208 forward andbackward to vary a thrust output of the engines 106, the throttle lever208 of the illustrated example has an aft limit (e.g., a lower limitthrottle setting) 212 and a fore limit (e.g., an upper limit throttlesetting) 214. In this example, the aft limit 212 and the fore limit 214define extreme ranges of the movement of the throttle lever 208, whichare not varied and/or redefined during flight in this example. In someexamples, however, a physical and/or electromagnetic device may be usedto limit the range of movement of the throttle lever 208. Additionallyor alternatively, ranges of the throttle lever 208 may be altered (e.g.,values of fore and aft limits redefined and/or varied to accommodatechanges in allowable range) instead of physically limiting a movementrange of the throttle lever 208 (e.g., in a fly-by-wire control system).

In some examples and as described in greater detail below in connectionwith FIG. 3, the aft limit 212 and/or the fore limit 214 may be variedand/or redefined (e.g., during flight and/or across different flightconditions) to vary a permitted range of an angle 218, which is denotedby the symbol, θ, at which the throttle lever 208 is positioned todefine an amount of thrust provided by the engines 106. In the examplesset forth herein, current (e.g., instantaneous) and/or controlledthrottle angles and/or set point values refer to the angle 218. Inparticular, the aft limit 212 of the illustrated example corresponds toa value of about 31 degrees relative to horizontal and the fore limit214 corresponds to a value of about 70 degrees relative to horizontal,thereby defining a maximum angular range (e.g., an angular displacementrange) of approximately 39 degrees for the throttle lever 208. However,any appropriate angle limits and/or range(s) may be used instead.

FIG. 3 illustrates an example throttle control plot 300 in accordancewith the teachings of this disclosure. The example throttle control plot300 relates velocity/speed and thrust ranges, and includes a horizontalaxis 302, which represents a calibrated air speed (“CAS”) and/orvelocity of the aircraft 100. The example control plot 300 also includesa vertical axis 304, which represents a throttle angle (e.g., a thrustresolver angle, the angle 218) of the aircraft 100. In this example, thethrottle angle is represented as degrees. In particular, in thisexample, the throttle angle is approximately 30 degrees (e.g., the aftlimit 212 at about 31 degrees). As can be seen in the illustratedexample of FIG. 3, the horizontal axis 302 includes a stick shakervelocity 306, which is denoted by V_(ss) and indicates a velocity limitat which a yoke stick such as the flight stick 202 may be shaken orvibrated to alert a pilot. In particular, a vibration devicecommunicatively coupled to the yoke stick may vibrate when a speed isbelow a threshold, which is equivalent to the stick shake velocity 306,for example. In this example, a transition velocity 308 is defined bytaking the maximum of a minimum speed (e.g., a minimum speed allowed byan automated flight control system), which is denoted by V_(cMin), or anincremental sum, which is denoted by V_(ss+10), of the shake speedvelocity 306, V_(ss), and an increment, which is 10 knots in thisexample. However, any appropriate incremental value may be used based onaircraft design, air conditions, aircraft maneuverability, etc. In thisexample, a maximum velocity 310 of the aircraft 100 is denoted byV_(cMax).

In this example, a boundary (e.g., an envelope, a polygonal area, etc.)defines a region 312 of the control plot 300 in which manual overrides(e.g., initiation of a hold command) of an autothrottle system areenabled. In other words, in the illustrated example, a pilot mayoverride an autothrottle system and place the autothrottle system into ahold mode within the region 312. Additionally or alternatively, theregion 312 may define an allowable/enabled throttle range (e.g.,continuously re-defining the aft limit 212 and/or the fore limit 214based on a flight condition and/or an updated flight condition). Inother words, the region 312 may also be used to limit a permittedthrottle range (e.g., an allowed/permitted throttle range) based onvelocity of the aircraft 100.

To define the region 312, the region 312 includes a first boundary oredge 314, which is defined by the velocity (e.g., V_(cMax)) 310, and asecond boundary or edge 316 that is defined by the throttle fore limit214. To define a function of throttle variation near calibrated airspeeds close to the stick shaker speed velocity 306, a sloping line 318defines a third boundary or edge representing a portion of the region312 where the manual override of the autothrottle may not be enabled.Additionally or alternatively, the sloping line 318 defines throttlelimits in which the throttle may be controlled and/or prevented frommoving as received in a flight input command (e.g., a manual command ora command initiating an automated program such as TOGA). Determinationof a slope of the line 318 is discussed in greater detail below inconnection with FIG. 4.

Alternatively, in some examples, a portion and/or outer limit of theregion 312 is defined by a fourth boundary or edge 320. In suchexamples, once the calibrated air speed has reached a value below atransition point 322, the automated/controlled thrust limit is preventedfrom moving below the fore limit (e.g., the fore limit 214) and/or, insome examples, a pilot is prevented from entering a hold mode thatplaces the thrust setting below the fore limit. In other words, in theseexamples, once a speed of the aircraft 100 is below a thresholdcorresponding to the transition point 322, the thrust resolver angle isnot enabled/permitted to be below the thrust fore limit in a controlledmode or, alternatively, in a manual mode.

In some examples, the region 312 is continuously defined/updated basedon changing flight condition(s). While the region 312 has an exampleshape shown in FIG. 3, any appropriate shape may be used.

FIG. 4 is a schematic overview of an example algorithm 400 to implementthe examples disclosed herein. In the illustrated example of FIG. 4, acalibrated air speed 402, which is denoted by CAS, as well as the stickshaker velocity 306, which is denoted by V_(ss), are provided as inputsto a function 408. In some examples, a low end speed value 406, which isalso provided to the function 408, is calculated as a maximum of(V_(CMIN), V_(ss+10)), where V_(CMIN) is a minimum control speed of theaircraft, and where V_(ss) is the aforementioned stick shaker velocity306 and V_(ss+10) is the incremental stick shaker speed equivalent tothe velocity 306 plus an added nominal speed, which is 10 knots in thisexample. However, any other appropriate additive nominal speed may beused based on aircraft design, flight conditions, flight mode, etc. Inthis example, the function 408 is used to calculate the slope and/ordefine the sloping line 318 (e.g., define a linear function of thesloping line 318). The calculation of the function 408 is representedbelow as Equation 1:

$\begin{matrix}{{{Throttle}\mspace{14mu} {slope}} = {\frac{\left( {{CAS} - {Vss}} \right)}{\left( {{{Maximum}\mspace{14mu} {of}\mspace{14mu} \left( {{VcMin},V_{{ss} + 10}} \right)} - V_{SS}} \right)}*{Throttle}\mspace{14mu} {Angle}\mspace{14mu} {Range}}} & (1)\end{matrix}$

In this example, the stick shaker velocity 306 (V_(ss)) is a function ofaircraft flight conditions measured by one or more sensors of theaircraft. In particular, the stick shaker velocity 306 may be calculatedbased on altitude and/or attitude of the aircraft. In some examples,V_(ss) may be a function of a lower speed limit such as the minimumcontrol speed (e.g., 1.3 times the minimum control speed).

In this example, once the slope of the function 408 is calculated, a lagfilter 409 is used to smooth and/or reduce noise of the output of thefunction 408. In some examples, a rate limiter 410 is used to limitrates of changes of the throttle angles. A range limit 412 then resolvesthe calculated slope from the calculation 408 to the angular range ofthe throttle, which ranges from 0 to 39 degrees in this example, todefine a lower angular limit. In particular, the angular range of 0 to39 degrees in this example is defined by an autothrottle aft limit of 31degrees while an aft stop is 33 degrees and a climb thrust point is 68degrees. In this example, the highest autothrottle point is 70 degreesand the corresponding physical stop is at 80 degrees. As a result, thehighest throttle point at 70 degrees minus the autothrottle aft limit of31 degrees yields the 39 degree range.

Next, a maximum throttle angle limit (e.g., a maximum aft limit value)414 is provided along with the lower angular limit from the range limit412 to a mathematical operation (e.g., an additive or a subtractiveoperation, etc.) 416 to determine a calculated/modified aft limit (e.g.,a limit of the aft limit 212) 418 for performance enhancement of theaircraft and/or to maintain the aircraft in a preferred flight condition(e.g., maintain a velocity above the stick shaker velocity, V_(ss), or amultiple of the stick shaker velocity). The mathematical operation 416may be represented by Equation 2 below, for example:

Modified Throttle Aft Limit=Maximum Throttle Angle Limit−RangeLimit  (2)

While the example calculations and/or signal filtering are shown abovein the examples described in connection with FIG. 4, any appropriateequations, values, operations and/or filtering may be used.

FIG. 5 is an example throttle control system (e.g., an automatedthrottle control system) 500 that may be used to implement the examplesdisclosed herein. The example throttle control system 500 includes aflight throttle computation system 502, which includes a flight throttlecalculator 504, a flight sensor interface 506 and a flight inputinterface 508. The control system 500 of the illustrated example alsoincludes an aircraft throttle system 510, which is communicativelycoupled to the flight input interface 508 via communication lines 512and to the flight throttle calculator 504 via communication lines 514.

In operation, the example flight sensor interface 506 determines flightconditions of an aircraft, such as the aircraft 100. In particular, theflight sensor interface 506 may determine flight conditions such as acalibrated airspeed, altitude, wind speed, attitude, terrain topography,weather conditions, air temperature and/or flight orientation (e.g.,yaw, pitch, roll, etc.), etc. based on sensor data and/or an analysis ofthe sensor data. In this example, the flight input interface 508receives flight inputs, which may be manual controls (e.g., a manualcontrol of the flight throttle) and/or flight mode commands (e.g.,changing the aircraft to a FLCH and/or VNAV automated mode).

To determine/calculate the preferred and/or allowable throttle setpoints and/or ranges, the flight throttle calculator 504 of theillustrated example utilizes the calibrated airspeed along with theaforementioned flight conditions and/or a stick shaker speed (V_(ss)) todetermine/calculate a preferred and/or allowable throttle range (e.g.,the adjusted aft limit 212). For example, the flight throttle calculator504 may use a defined region such as the region 312 of FIG. 3. Once thepreferred and/or allowable throttle range(s) have been determined, theflight throttle calculator 504 of the illustrated example directs theaircraft throttle system 510 to maintain the throttle within thepreferred and/or allowable throttle range(s). For example, the aircraftthrottle calculator 504 may direct the throttle system 510 not to enableinitiation of a hold mode if the throttle is moved out of the preferredand/or allowable throttle range(s) based on a received flight input. Inparticular, the flight throttle control system 502 and/or the flightthrottle calculator 504 prevent the aircraft throttle system 510 fromexecuting an input command to place the aircraft from an autothrottlemode into a hold/manual control mode based on the calculated preferredand/or allowable throttle range(s), for example. Additionally oralternatively, the flight throttle calculator 504 and/or the flightinput interface 508 direct the aircraft throttle system 510 to maintainthe throttle within the preferred and/or allowable throttle range(s) byvarying an aft limit of the throttle, for example.

While an example manner of implementing the example throttle controlsystem 500 of FIG. 5 is illustrated in FIG. 5, one or more of theelements, processes and/or devices illustrated in FIG. 5 may becombined, divided, re-arranged, omitted, eliminated and/or implementedin any other way. Further, the example flight throttle computationsystem 502, the example flight throttle calculator 504, the exampleflight sensor interface 506, the example flight input interface 508and/or, more generally, the example throttle control system 500 of FIG.5 may be implemented by hardware, software, firmware and/or anycombination of hardware, software and/or firmware. Thus, for example,any of the example flight throttle computation system 502, the exampleflight throttle calculator 504, the example flight sensor interface 506,the example flight input interface 508 and/or, more generally, theexample throttle control system 500 could be implemented by one or moreanalog or digital circuit(s), logic circuits, programmable processor(s),application specific integrated circuit(s) (ASIC(s)), programmable logicdevice(s) (PLD(s)) and/or field programmable logic device(s) (FPLD(s)).When reading any of the apparatus or system claims of this patent tocover a purely software and/or firmware implementation, at least one ofthe example, flight throttle computation system 502, the example flightthrottle calculator 504, the example flight sensor interface 506, and/orthe example flight input interface 508 is/are hereby expressly definedto include a tangible computer readable storage device or storage disksuch as a memory, a digital versatile disk (DVD), a compact disk (CD), aBlu-ray disk, etc. storing the software and/or firmware. Further still,the example throttle control system 500 of FIG. 5 may include one ormore elements, processes and/or devices in addition to, or instead of,those illustrated in FIG. 5, and/or may include more than one of any orall of the illustrated elements, processes and devices.

Flowcharts representative of example methods for implementing thethrottle control system 500 of FIG. 5 are shown in FIGS. 6-8. In theseexamples, the method may be implemented by machine readable instructionsthat comprise a program for execution by a processor such as theprocessor 912 shown in the example processor platform 900 discussedbelow in connection with FIG. 9. The program may be embodied in softwarestored on a tangible computer readable storage medium such as a CD-ROM,a floppy disk, a hard drive, a digital versatile disk (DVD), a Blu-raydisk, or a memory associated with the processor 912, but the entireprogram and/or parts thereof could alternatively be executed by a deviceother than the processor 912 and/or embodied in firmware or dedicatedhardware. Further, although the example program is described withreference to the flowcharts illustrated in FIGS. 6-8, many other methodsof implementing the example throttle control system 500 mayalternatively be used. For example, the order of execution of the blocksmay be changed, and/or some of the blocks described may be changed,eliminated, or combined.

As mentioned above, the example methods of FIGS. 6-8 may be implementedusing coded instructions (e.g., computer and/or machine readableinstructions) stored on a tangible computer readable storage medium suchas a hard disk drive, a flash memory, a read-only memory (ROM), acompact disk (CD), a digital versatile disk (DVD), a cache, arandom-access memory (RAM) and/or any other storage device or storagedisk in which information is stored for any duration (e.g., for extendedtime periods, permanently, for brief instances, for temporarilybuffering, and/or for caching of the information). As used herein, theterm tangible computer readable storage medium is expressly defined toinclude any type of computer readable storage device and/or storage diskand to exclude propagating signals and to exclude transmission media. Asused herein, “tangible computer readable storage medium” and “tangiblemachine readable storage medium” are used interchangeably. Additionallyor alternatively, the example methods of FIGS. 6-8 may be implementedusing coded instructions (e.g., computer and/or machine readableinstructions) stored on a non-transitory computer and/or machinereadable medium such as a hard disk drive, a flash memory, a read-onlymemory, a compact disk, a digital versatile disk, a cache, arandom-access memory and/or any other storage device or storage disk inwhich information is stored for any duration (e.g., for extended timeperiods, permanently, for brief instances, for temporarily buffering,and/or for caching of the information). As used herein, the termnon-transitory computer readable medium is expressly defined to includeany type of computer readable storage device and/or storage disk and toexclude propagating signals and to exclude transmission media. As usedherein, when the phrase “at least” is used as the transition term in apreamble of a claim, it is open-ended in the same manner as the term“comprising” is open ended.

The example method of FIG. 6 begins at block 600 where an aircraft suchas the aircraft 100 is in an automated flight level change mode (FLCH)in which the aircraft is changing altitude (e.g., an automated descent)(block 600). In this example, the autopilot is disengaged, but a flightdirector is on and provides guidance commands to a pilot of theaircraft. However, in regards to the example method of FIG. 6, theaircraft of the illustrated example may or may not be in an automatedflight mode.

A flight condition of the aircraft is determined (block 602). Inparticular, sensors communicatively coupled to a sensor interface suchas the flight sensor interface 506 provide information related to theaircraft including aircraft speed (e.g., calibrated aircraft speed),attitude, altitude, orientation, and/or air conditions. In someexamples, variables such as stick shaker speed (V_(ss)) and/or minimumspeeds (V_(cmin)), which may be used in calculations related topreferred and/or allowed throttle limits, are determined based on thisinformation.

Next, an allowable throttle limit (e.g., the aft limit 212) and/orthrottle range is calculated based on the flight condition (block 604).For example, an algorithm such as the algorithm 400 of FIG. 4 may beused to calculate the throttle limit and/or allowable throttle range.Additionally or alternatively, a boundary such as the region 312 of FIG.3 may be used in this calculation.

In this example, a throttle control (e.g., an automated throttlecontrol) is restricted based on the calculated throttle limit and/orrange (block 606). In some examples, the throttle control (e.g., thethrottle lever 208) is physically limited and/or varied via anelectromechanical system (e.g., an electromechanical restriction system)based on the calculated throttle limit and/or throttle range. In someexamples, the physical range of the throttle control is not varied, butthe throttle limits at an aft limit (e.g., the aft limit 212) and/or afore limit (e.g., the fore limit 214) are varied based on the calculatedallowable throttle limit and/or range. As a result, the throttle is,thus, prevented from placing the aircraft into a non-preferred stateand/or low performance condition regardless of the physical position ofthe throttle.

In this example, the process ends after the throttle control has beenrestricted (block 608). However, in some examples, the process repeatscontinuously during flight. Additionally or alternatively, the processis initiated and continues based on the aircraft being in a defined mode(e.g., an autothrottle enable mode).

Turning to FIG. 7, the example method of FIG. 7 begins at block 700where an aircraft such as the aircraft 100 of FIG. 1 is in an autopilotmode during cruise (block 700). In this example, an autothrottle systemof the aircraft is engaged. In contrast to the example of FIG. 6,instead of limiting a throttle limit and/or throttle range based onflight conditions and/or sensor data, a flight input is compared and/oranalyzed to determine whether the it is permissible for the flight inputto override the autothrottle system and/or place the autothrottlecontrol into a hold mode.

In this example, a flight condition of the aircraft is determined (block702). In particular, sensor data from sensors communicatively coupled toa flight sensor interface such as the flight sensor interface 506 isused to determine the flight condition.

Next, a flight input is received (block 704). In particular, an inputcommand from cockpit controls of the aircraft is received by a flightinterface such as the flight interface 508. For example, the input maybe a flight level change (FLCH) (e.g., a controlled descent) to adefined altitude. In some examples, the flight input may be a manualinput such as a manual throttle change (e.g., a throttle decrease,etc.).

In some examples, a status of an autothrottle control of the aircraft isdetermined (block 706). In such examples, a flight input interface suchas the flight input interface 508 may be queried to determine whetherthe autothrottle control is engaged. However, in this example, theautothrottle control of the aircraft is engaged and, thus, the status ofthe autothrottle control is known.

A throttle limit (e.g., the aft thrust limit 212) and/or throttle range(e.g., allowable throttle limit and/or range, thrust resolver angle,etc.) is calculated based on the flight condition (block 708). In thisexample, a flight throttle calculator such as the flight throttlecalculator 504 is used to determine the throttle limit and/or thethrottle range based on the flight conditions (e.g., calibrated airspeed, altitude, flight mode, air conditions, wind conditions, etc.). Tocalculate the allowable throttle angle and/or throttle range that willmaintain the aircraft in a preferred flight condition (e.g., a preferredflight state, a preferred flight mode, etc.), the flight throttlecalculator of the illustrated example utilizes an algorithm such as thealgorithm 400 of FIG. 4. Additionally or alternatively, the flight inputmay be also used in this calculation.

Next, it is determined whether to place the autothrottle into a holdmode (block 710). In this example, the flight input is compared to thecalculated allowable throttle limit and/or throttle range. Inparticular, if the flight input (e.g., a manual throttle change,initiation of an automated autopilot mode and/or program, etc.) willplace the aircraft outside of the preferred mode (e.g., below a V_(ss)speed such as the Vss speed 306), the autothrottle will not be allowedto be placed into the hold mode. For example, a comparison and/oranalysis illustrated by the throttle control plot 300 of FIG. 3 may beused to determine whether to allow a change in the autothrottle status(e.g., to disconnect, disengage, hold, activate, or change the mode ofthe autothrottle.).

If the autothrottle is not to be placed into the hold mode (block 710),control of the process returns to block 702. However, if theautothrottle is to be placed into the hold mode (block 710), the processproceeds to block 712 where the autothrottle is placed into the holdmode (block 712) and the process ends (block 714).

Turning to FIG. 8, the example method of FIG. 8 begins at block 800where an aircraft in flight is proceeding/trending (e.g., viainterpolation) to a non-preferred and/or lower performance flightcondition (e.g., a maneuver and/or altitude change) (block 800). In thisexample, the autothrottle mode is to be automatically changed as theaircraft proceeds or has proceeded into the non-preferred and/or lowerperformance regime.

In some examples, a status of the autothrottle system of the aircraft isdetected (block 802). For example, a flight input interface such as theflight input interface 508 may be used to communicate with cockpitcontrol of the aircraft to determine whether the autothrottle system isengaged, for example.

In some examples, the autothrottle is placed into the hold mode and/ordisengaged based on receiving a flight input (e.g., a manual control,initiation of an automated flight program, etc.) (block 804).

In this example, the flight input is analyzed based on the flightconditions (block 806). For example, the flight input is compared to acalculated flight throttle limit using the example algorithm 400 of FIG.4. Additionally or alternatively, the flight input is compared todefined velocity/thrust boundary (e.g., the region 312) pertaining to adefined preferred flight condition. This comparison may be used todetermine whether the flight input places the aircraft throttle out ofthe defined thrust/velocity boundaries or region(s).

Next, it is determined whether to change the mode of the autothrottle(block 808). In this example, the autothrottle mode is automaticallychanged based on whether the received flight input places the aircraftthrottle below a calculated throttle limit. Additionally oralternatively, the autothrottle mode is to be automatically changedbased on determining that the aircraft is trending towards anon-preferred condition (e.g., a rapid climb and/or speed decrease,trends away from a preferred flight state) although the aircraft is notyet in the non-preferred condition. If the autothrottle mode is not tobe changed (block 808), control of the process returns to block 802.

However, if the autothrottle mode is to be changed (block 808), controlof the process proceeds to block 810, where the autothrottle mode ischanged (block 810). In some examples, the autothrottle mode is changed(e.g., automatically changed) by overriding a hold mode of theautothrottle system.

After the autothrottle mode is changed (block 810), it is thendetermined whether the aircraft is in a preferred flight condition(block 812). For example, a sensor interface such as the flight sensorinterface 506 is used to determine whether the aircraft is within thepreferred flight condition (e.g., within the boundaries of the flightcontrol plot 300 and/or use of the algorithm 400 indicates that theaircraft is utilizing a throttle level above a calculated allowablethrottle limit/thrust resolver angle). Alternatively, in some examples,the aircraft is determined to be in the preferred flight condition ifthe velocity of the aircraft exceeds the stick shaker velocity, V_(ss)(e.g., exceeds a multiple of greater than 1.1-1.5 times the stick shakervelocity).

If the aircraft is not in the preferred flight condition (block 812),control of the process proceeds to block 814, where the autothrottlemode is maintained until the aircraft is placed into the preferredflight condition (block 814). In some examples, the autothrottle isprevented from entering the hold mode until the aircraft has reached thepreferred flight condition (e.g., a preferred velocity of the aircraftgiven an altitude and/or orientation of the aircraft). After theaircraft has reached the preferred flight condition, control of theprocess returns to the block 802.

In some examples, if the aircraft is in the preferred flight condition(block 812), control of the process proceeds to block 816, where it isdetermined whether to enable a manual override of the autothrottlesystem (block 816). In particular, the autothrottle system of theillustrated example is placed into a mode where a manual override of theautothrottle system is enabled as long as the aircraft is not trendingaway from the preferred flight condition. In other words, a hold mode ofthe autothrottle system is enabled based on the aircraft not trendingaway from the preferred flight condition. In this example, if the manualoverride is to be enabled, the manual override is enabled (block 817)and control of the process proceeds to block 802.

Alternatively, if the aircraft is trending away from the preferredflight condition while still within the preferred flight condition, themanual override of the autothrottle system is not enabled (block 816)and control of the process proceeds to block 814.

FIG. 9 is a block diagram of an example processor platform 900 capableof executing the example methods of FIGS. 6-8 to implement the examplethrottle control system 500 of FIG. 5. The processor platform 900 canbe, for example, a server, a personal computer, a mobile device (e.g., acell phone, a smart phone, a tablet such as an iPad™), a personaldigital assistant (PDA), an Internet appliance, a digital videorecorder, a set top box, or any other type of computing device.

The processor platform 900 of the illustrated example includes aprocessor 912. The processor 912 of the illustrated example is hardware.For example, the processor 912 can be implemented by one or moreintegrated circuits, logic circuits, microprocessors or controllers fromany desired family or manufacturer.

The processor 912 of the illustrated example includes a local memory 913(e.g., a cache). In this example, the processor 912 also includes theflight throttle calculator 504, the flight sensor interface 506, theflight input interface 508 and the aircraft throttle system 510. Theprocessor 912 of the illustrated example is in communication with a mainmemory including a volatile memory 914 and a non-volatile memory 916 viaa bus 918. The volatile memory 914 may be implemented by SynchronousDynamic Random Access Memory (SDRAM), Dynamic Random Access Memory(DRAM), RAMBUS Dynamic Random Access Memory (RDRAM) and/or any othertype of random access memory device. The non-volatile memory 916 may beimplemented by flash memory and/or any other desired type of memorydevice. Access to the main memory 914, 916 is controlled by a memorycontroller.

The processor platform 900 of the illustrated example also includes aninterface circuit 920. The interface circuit 920 may be implemented byany type of interface standard, such as an Ethernet interface, auniversal serial bus (USB), and/or a PCI express interface.

In the illustrated example, one or more input devices 922 are connectedto the interface circuit 920. The input device(s) 922 permit(s) a userto enter data and commands into the processor 912. The input device(s)can be implemented by, for example, an audio sensor, a microphone, acamera (still or video), a keyboard, a button, a mouse, a touchscreen, atrack-pad, a trackball, isopoint and/or a voice recognition system.

One or more output devices 924 are also connected to the interfacecircuit 920 of the illustrated example. The output devices 924 can beimplemented, for example, by display devices (e.g., a light emittingdiode (LED), an organic light emitting diode (OLED), a liquid crystaldisplay, a cathode ray tube display (CRT), a touchscreen, a tactileoutput device, a printer and/or speakers). The interface circuit 920 ofthe illustrated example, thus, typically includes a graphics drivercard, a graphics driver chip or a graphics driver processor.

The interface circuit 920 of the illustrated example also includes acommunication device such as a transmitter, a receiver, a transceiver, amodem and/or network interface card to facilitate exchange of data withexternal machines (e.g., computing devices of any kind) via a network926 (e.g., an Ethernet connection, a digital subscriber line (DSL), atelephone line, coaxial cable, a cellular telephone system, etc.).

The processor platform 900 of the illustrated example also includes oneor more mass storage devices 928 for storing software and/or data.Examples of such mass storage devices 928 include floppy disk drives,hard drive disks, compact disk drives, Blu-ray disk drives, RAIDsystems, and digital versatile disk (DVD) drives.

Coded instructions 932 of FIGS. 6-8 may be stored in the mass storagedevice 928, in the volatile memory 914, in the non-volatile memory 916,and/or on a removable tangible computer readable storage medium such asa CD or DVD.

From the foregoing, it will be appreciated that the above disclosedmethods, apparatus and articles of manufacture enable automated controlof throttle systems to automatically maintain an aircraft in a preferredstate and/or enhance performance of the aircraft. The examples disclosedherein allow automated throttle range control and/or systems to preventa throttle from moving past a calculated preferred throttle range. Theexamples disclosed herein also allow a system to prevent an autothrottlesystem from entering a hold/override mode based on flight conditionsand/or a flight input. The examples disclosed herein allow automatedthrottle systems to be automatically change modes to prevent theaircraft from moving into a non-preferred state.

Although certain example methods, apparatus and articles of manufacturehave been disclosed herein, the scope of coverage of this patent is notlimited thereto. On the contrary, this patent covers all methods,apparatus and articles of manufacture fairly falling within the scope ofthe claims of this patent. While the examples disclosed herein arerelated to aircraft, the examples disclosed may be applied to anyvehicles, space craft, submersibles, etc.

1. A method comprising: calculating, using a processor, a thrustresolver angle based on a flight condition of an aircraft; andcontrolling a throttle from moving past at least one of the thrustresolver angle or a range defined by the thrust resolver angle tomaintain the aircraft in a preferred flight mode, wherein controllingthe throttle includes preventing an autothrottle system from being putinto a hold mode that overrides the autothrottle system when theaircraft trends away from the preferred flight mode.
 2. The method asdefined in claim 1, wherein calculating the thrust resolver angle isfurther based on a selected automated mode of the aircraft.
 3. Themethod as defined in claim 1, wherein the flight condition includes atleast one of velocity, pitch, yaw, roll, or altitude of the aircraft. 4.The method as defined in claim 1, wherein calculating the thrustresolver angle is based on a region defined by velocity and thrustranges.
 5. The method as defined in claim 1, wherein controlling thethrottle includes restricting a range of movement of a throttle lever.6. The method as defined in claim 5, wherein restricting the throttleincludes electromechanical restriction of the throttle lever. 7.(canceled)
 8. The method as defined in claim 1, wherein the preferredflight mode includes maintaining the aircraft at a speed exceeding astick shaker velocity of the aircraft.
 9. A method for controlling anautothrottle control of an aircraft comprising: analyzing, using aprocessor, a received flight input and at least one flight condition todetermine whether the flight input will place the aircraft in a statedifferent from a preferred flight state; upon determining that theflight input will not place the aircraft in the state different from thepreferred flight state, enabling the autothrottle control to be placedinto a hold mode that overrides the autothrottle control; andautomatically preventing the autothrottle control from entering the holdmode when the aircraft trends away from the preferred flight state. 10.The method as defined in claim 9, further including upon determiningthat the flight input will place the aircraft in the state differentfrom the preferred flight state, automatically changing a mode of theautothrottle control.
 11. (canceled)
 12. The method as defined in claim9, further including controlling a throttle level above a thrustresolver angle, wherein the thrust resolver angle is based on a regiondefined by velocity and thrust ranges.
 13. The method as defined inclaim 9, wherein the preferred flight state includes a velocity greaterthan a stick shaker velocity of the aircraft.
 14. A tangible machinereadable medium having instructions stored thereon, which when executed,cause a processor to: determine that a flight input of an aircraft willcause the aircraft to be in a non-preferred flight condition; and basedon the determination, prevent an autothrottle mode of the aircraft fromentering a hold mode that overrides the autothrottle mode to maintainthe aircraft in a preferred flight condition.
 15. The machine readablemedium having instructions stored thereon as defined in claim 14, whichwhen executed, further cause the processor to calculate at least one ofan allowable throttle limit or throttle range.
 16. The machine readablemedium having instructions stored thereon as defined in claim 15, whichwhen executed, further cause the processor to direct anelectromechanical system to inhibit motion of a throttle lever beyondthe at least one of the allowable throttle limit or throttle range. 17.The machine readable medium having instructions stored thereon asdefined in claim 14, wherein the flight input includes a command toperform an automated flight program.
 18. The machine readable mediumhaving instructions stored thereon as defined in claim 14, wherein theflight input includes a manual input.
 19. The machine readable mediumhaving instructions stored thereon as defined in claim 14, wherein theprocessor determines that the aircraft is trending away from thepreferred flight condition to determine that the flight input will causethe aircraft to be in the non-preferred flight condition.
 20. Anapparatus comprising: a sensor of an aircraft to determine a flightcondition of the aircraft; a processor to calculate at least one of athrottle limit or a throttle range based on the flight condition and aflight input to maintain the aircraft in a preferred flight condition,wherein the processor is to prevent an automated throttle control systemof the aircraft from entering a hold mode that overrides the automatedthrottle control system based on the flight input trending the aircraftaway from the preferred flight condition; and an electromechanicalmechanism to control a throttle lever from moving beyond the at leastone of the throttle limit or the throttle range.
 21. The apparatus asdefined in claim 20, wherein the processor is to calculate the at leastone of the throttle limit or the throttle range by comparing an airspeedof the aircraft to a region defined by velocity and thrust ranges. 22.The apparatus as defined in claim 20, wherein the processor is tocalculate the at least one of the throttle limit or the throttle rangefurther based on the flight input.
 23. (canceled)